Apparatus for grinding and polishing precious stones



May 11 1926. 1,583,963

w. A. DONALDSON APPARATUS FOR GRINDING AND POLISHING PRECIOUS s'roNEs Filed May 7. 1923 2 Sheets-Sheet 1 INVENTOR. Mflonaldson TTORNEY.

W. A. DONALDSON APPARATUS FOR GRI NDING AND POLISHING PRECIOUS STOfiES Fi led May '7. 1925 2 Sheets-Sheet 2 INVENTOR. wfz'ipdflaldson ATTORNEY.

Patented May 11, 1926.

warren SATE'ES' raft WILLIAIVI ARTHUR DONALDSON, OF BROOKLYN, NEW YORK.

APPARATUS FOR GRINDING AND POLISHING PRECIOUS STONES.

Application filed May 7,

This invention relates to apparatus for grinding and polishing precious stones, having reference particularly to improved means for supporting and adjusting a stone-carry ing dop in proper correlation with a lap.

The invention has for an object the provision of means for accurately placing and holding a precious stone over the horizontal plane surface'oi the lap at various angles to its axis; a further object being to provide means for accurately gaging the adjustments for the production of facets of uniform angles and widths.

In carrying out my invention, I employ a bracket comprising a standard or tang having a horizontally extended arm, and a rotatable, vertically adjustable spindle extended through the free end of said arm and having an elongated head, a Slide horizontally adjustable on said head, a swingingly mounted dop holder carried by said slide and comprising two members in turnably adjustable correlation with each other, means connecting said head with said dop holder, whereby longitudinal movement of said slide automatically swings the dop holder, and gage means for indicating the movements of said parts, and other novel features hereinafter fully described and specifically set forth in the appended claims.

In the accompanying drawings forming part of this specification, Figure 1 is a plan view illustrating an embodiment of my invention.

Fig. 2 is a side view;

Fig. 3 is a vertical sectional view taken on the line S-3 of Fig. 2; V

Fig. 1 is a fragmentary sectional view taken on the same line and drawn on an enlarged scale;

Fig. 5 is a fragmentary side view;

Fig. 6 is a plan view of a detail of the device; and v Fig. 7 is a sectional view of a fragment of the dop.

In the drawings, 1 indicates the bracket, which embodies an arched standard 2 and a horizontal arm 3, said brac :et being adapted to be adjustably mounted on a table 5 adjacent a lap indicated by 6. The standard arm 2 is provided with the usual horizontally disposed rod 7 held against lateral displacement by abutting against a vertical pin 8 forming part of an adjustable plate 10, said plate having a slot 11 through which extends 'a bolt 12 which is fixed to the table 5, a

1923. Serial No. 637,238.

thumb-nut being employed for maintaining the plate 10 in set relation. A. pin 9 is also provided for lateral bearingrelation with the arm 3, and a slidable sleeve 13 is mounted on said pin and is provided with a bearing-ledge 1 for supporting the forward end of the arm 8 and maintaining said arm in level horizontal position, said sleeve adapted to be maintained in set position by means oi a set-screw 15.

In vertically adjustable connection with the forward or free end of the arm 3 is a scrcwsleeve 16 which is in threaded relalion through sait. free end and is adapted to F be held in arbitrarily set position by means of a loclenut 17. I

hrough the sleeve 16 extends a spindle 16 which is adapted to be turned independently oi the sleeve 16 and held in set relation cable bearing relation with a lug 21 of the guide-plate 21. c

Swingingly engaging the slide 23, by means of a pivot 25, is the dop holder comprising the upper section 26 and lower section 27, said sections being coupled by means of a screw 28 having ahead 28 which snugly fits within a recess 27 of the section 27. The sections 26 and 27 have interlocking teeth, shown at a, Figs. 2 and 5 of the drawings, and they are maintained in yieldingly coupled relation by means of a helical spring 29 placed between the head 28 oi the screw 28 and the inner end surface of the recess 27, whereby when the section 27 is turned around the axis of the screw 28 the same is slidably movable on the head 28. Communicating with the recess 27 is a recess 27 for the accommodation of a dop 80, said dop having a recess 30 for receiving a precious stone, as 31, said stone being held in place by means of a claw 32 mounted on the lower end of a slidably adjustable pin 33 which passes through a bearing 26 formed integral with the section 26 of (the dop holder, set screw 84: being employed for holding said pm in properly set relation."

The dop 30 is longitudinall split, as

shown at b, Fig. at of the d'ra' 'ings thus the diameter or" the opening of the recess 30 may be slightly varied by means of a set-screw 35, whereby in conjunction with the claw 32 the stone may be held in securely :i fixed relation, and the dop is held against liability of accidental displacement bymeans bushing39 set within the recess 30.

Connecting the upper section 26 of the dop holder with the guide-plate 21 of the spindle 18, are swinging connecting rods alt), whereby when the slide 23 is moved in the direction of the arrow 0, Fig: 5 of the drawings, the dop is swung in the opposite direction.

4 Zero mark ll is provided on one side of the plate 2t which registerswith a similar mark e2, on the slide 23, when the dop is positioned at right angles to the horizontal surface of said plate, and a calibrated scale is provided to r registration with the mark 4 2, whereby the dop may be set at a desirable degree in relation to the axis of the soindle 18. r

T he peripheral surface of the dop holder section 26 is provisioned with a zero point for registration with a peripheral scale slat, whereby the'dop may be turned and set tor producing facets ottherequired width, the

spring 29 ad'mitt-ing'of t-nrnable i'noveinent of the section 27 on the section 26, but holding the sections 26 and QTagainst turnable movement during the grinding and polishing process.

In the operation and use of this invention it is manifest that owing to the novel correlation of the'several parts and the simple indicator means acting in conjunction:therewith, an operator may very accurately gage his work for the production of facets of equal widths and uniform angles.

Having thus described my invention what 1 claim new and dcsireto secure by Letters Patent, is: i

1. In an apparatus for grinding and polishing precious stones, in combination with a bracket adapted for extension over a lap. a rotatable and vertically adjustable spindle having ahead embodying an' elongated guide, a slide horizontally, adjustable on said guide, a swingingfldop holder, and

.means connecting said dop holder with said gu de whereby movement of said slide automatically swings the dop holder.

lap, rotatable and vertically adjustablea spindle having a head embodying a horizontal guide, a slide horizontally, adjustable on said guide,a swinging dopiholder comprising two sections, one rotatable on the other, means yieldingly connecting said sections, and means connecting asdop to the lower one of said sections, and a yoke for connecting said dop holder with said: guide whereby movement of the slide swings the dop holder.

In an apparatus for grinding and polishing precious stones, a vertical spindle having an elongated. horizontal part on its head constituting a guide and a slide horizontally movable on said guide, and a swinging dop holder pivoted to said slide, said guide having a scale; whosegraduations radiate from the pivot of said dopl holder, said dop holder having, a pointerlfor. ,lfegistratiion over: said scale, and means connecting said dop holder witlrsaid. uide whereby movement of the slide automatically swings said dop holder.

5. In an apparatusfor grinding and polconstituting a guide. and a slide horizontally. movable on said guide, and a swinging dop.

.holder pivoted to said slide, said dop holder comprising two. sections n yieldingly 1 rotatable connection with each other, said sections having interlocking teeth, one of said sections having an annular scale andv the other having anindicator mark registering with said scale, the turnable section having means for fastening a-idop. v

Signed-at New York in New =York i and State of New York this 28th day of A1L ril A. D; $23.:

wILLnuu ARTHUR noNlLD'soN.

' ishing precious stones, avertical spindlehav:

.ing an elongated horizontal part; on its head the county of 

